diff --git a/packages/happy-dom/src/index.ts b/packages/happy-dom/src/index.ts
index 74d7c43e..8f984ea3 100644
--- a/packages/happy-dom/src/index.ts
+++ b/packages/happy-dom/src/index.ts
@@ -70,6 +70,7 @@ import DocumentFragment from './nodes/document-fragment/DocumentFragment.js';
 import DocumentType from './nodes/document-type/DocumentType.js';
 import Document from './nodes/document/Document.js';
 import DOMRect from './nodes/element/DOMRect.js';
+import DOMRectReadOnly from './nodes/element/DOMRectReadOnly.js';
 import Element from './nodes/element/Element.js';
 import HTMLCollection from './nodes/element/HTMLCollection.js';
 import HTMLAnchorElement from './nodes/html-anchor-element/HTMLAnchorElement.js';
@@ -211,6 +212,7 @@ export {
 	DOMException,
 	DOMParser,
 	DOMRect,
+	DOMRectReadOnly,
 	DataTransfer,
 	DataTransferItem,
 	DataTransferItemList,
diff --git a/packages/happy-dom/src/nodes/element/DOMRect.ts b/packages/happy-dom/src/nodes/element/DOMRect.ts
index 0305962a..86d433a6 100644
--- a/packages/happy-dom/src/nodes/element/DOMRect.ts
+++ b/packages/happy-dom/src/nodes/element/DOMRect.ts
@@ -1,30 +1,47 @@
+import DOMRectReadOnly, { IDOMRectInit } from './DOMRectReadOnly.js';
+import * as PropertySymbol from '../../PropertySymbol.js';
+
+/* eslint-disable jsdoc/require-jsdoc */
+
 /**
  * Bounding rect object.
  *
  * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMRect
  */
-export default class DOMRect {
-	public x = 0;
-	public y = 0;
-	public width = 0;
-	public height = 0;
-	public top = 0;
-	public right = 0;
-	public bottom = 0;
-	public left = 0;
-
-	/**
-	 * Constructor.
-	 *
-	 * @param [x] X position.
-	 * @param [y] Y position.
-	 * @param [width] Width.
-	 * @param [height] Height.
-	 */
-	constructor(x?, y?, width?, height?) {
-		this.x = x || 0;
-		this.y = y || 0;
-		this.width = width || 0;
-		this.height = height || 0;
+export default class DOMRect extends DOMRectReadOnly {
+	public set x(value: number) {
+		this[PropertySymbol.x] = value;
+	}
+
+	public get x(): number {
+		return this[PropertySymbol.x];
+	}
+
+	public set y(value: number) {
+		this[PropertySymbol.y] = value;
+	}
+
+	public get y(): number {
+		return this[PropertySymbol.y];
+	}
+
+	public set width(value: number) {
+		this[PropertySymbol.width] = value;
+	}
+
+	public get width(): number {
+		return this[PropertySymbol.width];
+	}
+
+	public set height(value: number) {
+		this[PropertySymbol.height] = value;
+	}
+
+	public get height(): number {
+		return this[PropertySymbol.height];
+	}
+
+	public static fromRect(other: IDOMRectInit): DOMRect {
+		return new DOMRect(other.x, other.y, other.width, other.height);
 	}
 }
diff --git a/packages/happy-dom/src/nodes/element/DOMRectReadOnly.ts b/packages/happy-dom/src/nodes/element/DOMRectReadOnly.ts
new file mode 100644
index 00000000..65c8bc33
--- /dev/null
+++ b/packages/happy-dom/src/nodes/element/DOMRectReadOnly.ts
@@ -0,0 +1,86 @@
+import * as PropertySymbol from '../../PropertySymbol.js';
+
+/* eslint-disable jsdoc/require-jsdoc */
+
+/**
+ * Bounding rect readonly object.
+ *
+ * @see https://drafts.fxtf.org/geometry/#DOMRect
+ */
+export default class DOMRectReadOnly implements IDOMRectInit {
+	protected [PropertySymbol.x]: number = 0;
+	protected [PropertySymbol.y]: number = 0;
+	protected [PropertySymbol.width]: number = 0;
+	protected [PropertySymbol.height]: number = 0;
+
+	/**
+	 * Constructor.
+	 *
+	 * @param [x] X position.
+	 * @param [y] Y position.
+	 * @param [width] Width.
+	 * @param [height] Height.
+	 */
+	constructor(x?: number | null, y?: number | null, width?: number | null, height?: number | null) {
+		this[PropertySymbol.x] = x !== undefined && x !== null ? Number(x) : 0;
+		this[PropertySymbol.y] = y !== undefined && y !== null ? Number(y) : 0;
+		this[PropertySymbol.width] = width !== undefined && width !== null ? Number(width) : 0;
+		this[PropertySymbol.height] = height !== undefined && height !== null ? Number(height) : 0;
+	}
+
+	public get x(): number {
+		return this[PropertySymbol.x];
+	}
+
+	public get y(): number {
+		return this[PropertySymbol.y];
+	}
+
+	public get width(): number {
+		return this[PropertySymbol.width];
+	}
+
+	public get height(): number {
+		return this[PropertySymbol.height];
+	}
+
+	public get top(): number {
+		return Math.min(this[PropertySymbol.y], this[PropertySymbol.y] + this[PropertySymbol.height]);
+	}
+
+	public get right(): number {
+		return Math.max(this[PropertySymbol.x], this[PropertySymbol.x] + this[PropertySymbol.width]);
+	}
+
+	public get bottom(): number {
+		return Math.max(this[PropertySymbol.y], this[PropertySymbol.y] + this[PropertySymbol.height]);
+	}
+
+	public get left(): number {
+		return Math.min(this[PropertySymbol.x], this[PropertySymbol.x] + this[PropertySymbol.width]);
+	}
+
+	public toJSON(): object {
+		return {
+			x: this.x,
+			y: this.y,
+			width: this.width,
+			height: this.height,
+			top: this.top,
+			right: this.right,
+			bottom: this.bottom,
+			left: this.left
+		};
+	}
+
+	public static fromRect(other: IDOMRectInit): DOMRectReadOnly {
+		return new DOMRectReadOnly(other.x, other.y, other.width, other.height);
+	}
+}
+
+export interface IDOMRectInit {
+	readonly x: number;
+	readonly y: number;
+	readonly width: number;
+	readonly height: number;
+}
diff --git a/packages/happy-dom/src/window/BrowserWindow.ts b/packages/happy-dom/src/window/BrowserWindow.ts
index b3573f39..70a6e827 100644
--- a/packages/happy-dom/src/window/BrowserWindow.ts
+++ b/packages/happy-dom/src/window/BrowserWindow.ts
@@ -97,6 +97,7 @@ import Plugin from '../navigator/Plugin.js';
 import PluginArray from '../navigator/PluginArray.js';
 import Fetch from '../fetch/Fetch.js';
 import DOMRect from '../nodes/element/DOMRect.js';
+import DOMRectReadOnly from '../nodes/element/DOMRectReadOnly.js';
 import VMGlobalPropertyScript from './VMGlobalPropertyScript.js';
 import VM from 'vm';
 import { Buffer } from 'buffer';
@@ -372,6 +373,7 @@ export default class BrowserWindow extends EventTarget implements INodeJSGlobal
 	public readonly PluginArray = PluginArray;
 	public readonly FileList = FileList;
 	public readonly DOMRect = DOMRect;
+	public readonly DOMRectReadOnly = DOMRectReadOnly;
 	public readonly RadioNodeList = RadioNodeList;
 	public readonly ValidityState = ValidityState;
 	public readonly Headers = Headers;
diff --git a/packages/happy-dom/test/nodes/element/DOMRect.test.ts b/packages/happy-dom/test/nodes/element/DOMRect.test.ts
new file mode 100644
index 00000000..b8a0b46c
--- /dev/null
+++ b/packages/happy-dom/test/nodes/element/DOMRect.test.ts
@@ -0,0 +1,156 @@
+import { afterEach, describe, it, expect, vi } from 'vitest';
+import DOMRect from '../../../src/nodes/element/DOMRect';
+
+describe('DOMRect', () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	describe('constructor()', () => {
+		it('Sets properties.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.x).toBe(1);
+			expect(rect.y).toBe(2);
+			expect(rect.width).toBe(3);
+			expect(rect.height).toBe(4);
+
+			const rect2 = new DOMRect(null, null, null, 4);
+			expect(rect2.x).toBe(0);
+			expect(rect2.y).toBe(0);
+			expect(rect2.width).toBe(0);
+			expect(rect2.height).toBe(4);
+
+			const rect3 = new DOMRect();
+			expect(rect3.x).toBe(0);
+			expect(rect3.y).toBe(0);
+			expect(rect3.width).toBe(0);
+			expect(rect3.height).toBe(0);
+
+			const rect4 = new DOMRect(
+				<number>(<unknown>'nan'),
+				<number>(<unknown>'nan'),
+				<number>(<unknown>'nan'),
+				<number>(<unknown>'nan')
+			);
+			expect(isNaN(rect4.x)).toBe(true);
+			expect(isNaN(rect4.y)).toBe(true);
+			expect(isNaN(rect4.width)).toBe(true);
+			expect(isNaN(rect4.height)).toBe(true);
+		});
+	});
+
+	describe('set x()', () => {
+		it('Sets rect x property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			rect.x = 2;
+			expect(rect.x).toBe(2);
+		});
+	});
+
+	describe('get x()', () => {
+		it('Returns rect x property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.x).toBe(1);
+		});
+	});
+
+	describe('set y()', () => {
+		it('Sets rect y property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			rect.y = 3;
+			expect(rect.y).toBe(3);
+		});
+	});
+
+	describe('get y()', () => {
+		it('Returns rect y property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.y).toBe(2);
+		});
+	});
+
+	describe('set width()', () => {
+		it('Sets rect y property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			rect.width = 4;
+			expect(rect.width).toBe(4);
+		});
+	});
+
+	describe('get width()', () => {
+		it('Returns rect y property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.width).toBe(3);
+		});
+	});
+
+	describe('set height()', () => {
+		it('Sets rect height property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			rect.height = 5;
+			expect(rect.height).toBe(5);
+		});
+	});
+
+	describe('get height()', () => {
+		it('Returns rect height property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.height).toBe(4);
+		});
+	});
+
+	describe('get top()', () => {
+		it('Returns rect top property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.top).toBe(2);
+		});
+	});
+
+	describe('get right()', () => {
+		it('Returns rect right property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.right).toBe(4);
+		});
+	});
+
+	describe('get bottom()', () => {
+		it('Returns rect bottom property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.bottom).toBe(6);
+		});
+	});
+
+	describe('get left()', () => {
+		it('Returns rect left property.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.left).toBe(1);
+		});
+	});
+
+	describe('fromRect()', () => {
+		it('Creates DOMRect instance', () => {
+			const rect = DOMRect.fromRect({ x: 1, y: 2, width: 3, height: 4 });
+			expect(rect instanceof DOMRect).toBe(true);
+			expect(rect.x).toBe(1);
+			expect(rect.y).toBe(2);
+			expect(rect.width).toBe(3);
+			expect(rect.height).toBe(4);
+		});
+	});
+
+	describe('toJSON()', () => {
+		it('Returns rect as JSON.', () => {
+			const rect = new DOMRect(1, 2, 3, 4);
+			expect(rect.toJSON()).toEqual({
+				x: 1,
+				y: 2,
+				width: 3,
+				height: 4,
+				top: 2,
+				right: 4,
+				bottom: 6,
+				left: 1
+			});
+		});
+	});
+});
diff --git a/packages/happy-dom/test/nodes/element/DOMRectReadOnly.test.ts b/packages/happy-dom/test/nodes/element/DOMRectReadOnly.test.ts
new file mode 100644
index 00000000..c179eeda
--- /dev/null
+++ b/packages/happy-dom/test/nodes/element/DOMRectReadOnly.test.ts
@@ -0,0 +1,124 @@
+import { afterEach, describe, it, expect, vi } from 'vitest';
+import DOMRectReadOnly from '../../../src/nodes/element/DOMRectReadOnly';
+
+describe('DOMRectReadOnly', () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	describe('constructor()', () => {
+		it('Sets properties.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.x).toBe(1);
+			expect(rect.y).toBe(2);
+			expect(rect.width).toBe(3);
+			expect(rect.height).toBe(4);
+
+			const rect2 = new DOMRectReadOnly(null, null, null, 4);
+			expect(rect2.x).toBe(0);
+			expect(rect2.y).toBe(0);
+			expect(rect2.width).toBe(0);
+			expect(rect2.height).toBe(4);
+
+			const rect3 = new DOMRectReadOnly();
+			expect(rect3.x).toBe(0);
+			expect(rect3.y).toBe(0);
+			expect(rect3.width).toBe(0);
+			expect(rect3.height).toBe(0);
+
+			const rect4 = new DOMRectReadOnly(
+				<number>(<unknown>'nan'),
+				<number>(<unknown>'nan'),
+				<number>(<unknown>'nan'),
+				<number>(<unknown>'nan')
+			);
+			expect(isNaN(rect4.x)).toBe(true);
+			expect(isNaN(rect4.y)).toBe(true);
+			expect(isNaN(rect4.width)).toBe(true);
+			expect(isNaN(rect4.height)).toBe(true);
+		});
+	});
+
+	describe('get x()', () => {
+		it('Returns rect x property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.x).toBe(1);
+		});
+	});
+
+	describe('get y()', () => {
+		it('Returns rect y property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.y).toBe(2);
+		});
+	});
+
+	describe('get width()', () => {
+		it('Returns rect y property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.width).toBe(3);
+		});
+	});
+
+	describe('get height()', () => {
+		it('Returns rect height property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.height).toBe(4);
+		});
+	});
+
+	describe('get top()', () => {
+		it('Returns rect top property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.top).toBe(2);
+		});
+	});
+
+	describe('get right()', () => {
+		it('Returns rect right property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.right).toBe(4);
+		});
+	});
+
+	describe('get bottom()', () => {
+		it('Returns rect bottom property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.bottom).toBe(6);
+		});
+	});
+
+	describe('get left()', () => {
+		it('Returns rect left property.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.left).toBe(1);
+		});
+	});
+
+	describe('fromRect()', () => {
+		it('Creates DOMRectReadOnly instance', () => {
+			const rect = DOMRectReadOnly.fromRect({ x: 1, y: 2, width: 3, height: 4 });
+			expect(rect instanceof DOMRectReadOnly).toBe(true);
+			expect(rect.x).toBe(1);
+			expect(rect.y).toBe(2);
+			expect(rect.width).toBe(3);
+			expect(rect.height).toBe(4);
+		});
+	});
+
+	describe('toJSON()', () => {
+		it('Returns rect as JSON.', () => {
+			const rect = new DOMRectReadOnly(1, 2, 3, 4);
+			expect(rect.toJSON()).toEqual({
+				x: 1,
+				y: 2,
+				width: 3,
+				height: 4,
+				top: 2,
+				right: 4,
+				bottom: 6,
+				left: 1
+			});
+		});
+	});
+});